HAMILTON, Ontario, March 13 (Reuters) - Sean Donnelly, Chief Executive of ArcelorMittal Dofasco, said on Tuesday the company is not seeking Canadian government aid as the domestic steel industry faces uncertainty after U.S. President Donald Trump provided temporary relief on steel imports.

Donnelly also said the Canadian government must put resources in place to ensure that cheap steel is not diverted into Canada after Trump last week decided to impose a 25 percent tariffs on steel imports.

While Canada and Mexico secured a temporary reprieve, Trump has linked permanent exemption to a successful North American Free Trade Agreement deal, making the industry nervous.

Canada is the biggest supplier of steel and aluminum to the United States. But relative to bigger industries such as agriculture and auto manufacturing, the steel sector only employs 22,000 direct jobs and represented 2 percent of exports last year.

ArcelorMittal is the largest steel manufacturer in Canada, employing about 10,300 people with seven units in the country, according to the Canadian Steel Producers Association (CSPA).

"I think it's just boots on the ground, boots on the ground both at the CBSA (Canada Border Services Agency) and in Global Affairs to make sure whatever remedies are put in place and that's up to the government to come up with the remedies or tools ...that they have the resources to enforce," Donnelly told Reuters.

Donnelly was speaking as Canadian Prime Minister Justin Trudeau visited the steel city of Hamilton to reassure workers, as part of his week-long tour to defend Canadian jobs. On Monday, Trudeau called Trump to stress the need to preserve the "mutually beneficial" cross border supply chains.

The North American steel industry is heavily integrated, with raw materials, steel and parts crossing the U.S.-Canadian border several times before a finished product such as a vehicle or refrigerator is sold to consumers. About 65 percent of the Hamilton port's tonnage is iron ore and coal used to make steel.

Hamilton, with a population of 700,000, houses Dofasco's mill, coking and finishing operations at Stelco and collection of smaller operations that directly employ about 10,000 people in the city. (Reporting by Allison Martell; Writing by Denny Thomas; Editing by Chizu Nomiyama and Grant McCool)